As a basis for understanding the problems with which the present invention is involved, reference is made to the following definition by Robert P. Morehead in Human Pathology, the Blakiston Division, McGraw-Hill Book Co., New York, 1965, Page 1507.
Serofibrinous Pleuritis (Pleurisy with effusion); a detectable exudate within the pleural cavity indicates rather extensive pleural involvement by infection, tumor or pulmonary infarction. Of the etiologic factors, infection in contiguous structures particularly pulmonary tuberculosis is by far the most important in persons under forty; in later years, cancer is the most important. Dyspnea and pain on inspiration are the principal symptoms. Since the visceral pleura is insensitive, pain is due to involvement of the parietal pleura and adjacent tissues. Dyspnea results when a large volume of fluid encroaches on the lung or when motion of the chest is restricted because of severe pain. X-ray examination will confirm the physical findings indicating fluid in the chest. Examination of pleural fluid obtained by thoracentesis gives the most accurate information as to the true nature of the effusion. Exudates may be differentiated from transudates by determining the specific gravity and total protein content of the fluid. Exfoliative cytology may be helpful in establishing the cause of those cases in which the effusion is secondary to a malignant tumor.
Stanley L. Robbins in Textbook of Pathology, W. B. Saunders Co., Philadelphia, 1964, Page 595 further adds: "It is frequently quite important to be able to differentiate a serous or serofibrinous exudate of inflammatory origin from a simple transudate of circulatory origin. In general, the serofibrinous exudates consist of relatively clear, limpid, straw-colored fluid in which, occasionally, small strands of opaque, yellow-white fibrin may be found floating. The specific gravity of these fluids tends, on the whole, to be greater than 1.016 to 1,020 and frequently, by centrifugation, scattered lymphocytes, macrophages, and a few polymorphonuclear neutrophiles, as well as the ever-present mesothelial cells, can be found within the sediment."
The total protein content of such exudates is greater than 0.6 mg. protein /100 ml. and is usually greater than 3.0 gm. protein /100 ml.
In the cases with which the present invention is concerned, large volumes of serofibrinous or bloody fluid are present. The volume obtained may range from 600 ml. to more than two liters. These effusions tend to recur in corresponding volumes at an early date when treated only by standard thoracentesis, necessitating repeated hospitalizations and additional tappings.